Floristic and Biogeographical Trends in Seaweed Assemblages from a Subtropical Insular Island Complex in the Gulf of California

Floristic and biogeographical trends of the seaweed assemblages in subtidial rocky areas were evaluated at 10 sites around Espiritu Santo Island in the Gulf of California. Seasonal sampling in two consecutive years with intensive surveys in a 500-m2 area at each site was done. An intensive search was made of previous records from the literature. We found 85 species in the field with an additional 69 species from the literature, for a total 116 species. Species composition was significantly different between sides of the island in the first year, but very similar in the second. Species composition was not influenced by the presence of epiphytes. Phenologically, most species were ephemeral or annual with a low reproductive effort. Biogeographically, tropical elements dominated, but there was an important contribution from temperate species. Our results indicate that Espiritu Santo Island is a dynamic system that is strongly influenced by local oceanographic conditions

Taxonomy and distribution of rhodolith beds from the Azores, Portugal.

2nd International Rhodolith Workshop. Ciencias Marinas, Universidad Autónoma de Baja California Sur, La Paz, B.C.S., México, 23-29 de Outubro de 2006

Morphological and anatomical observations on the genus Scinaia (Nemaliales; Rhodophyta) from the Gulf of California, Mexico.

43rd European Marine Biology Symposium. Ponta Delgada, Açores, 8-12 de Setembro de 2008

Rhodoliths and rhodolith beds

Rhodolith (maërl) beds, communities dominated by free living coralline algae, are a common feature of subtidal environments worldwide. Well preserved as fossils, they have long been recognized as important carbonate producers and paleoenvironmental indicators. Coralline algae produce growth bands with a morphology and chemistry that record environmental variation. Rhodoliths are hard but often fragile, and growth rates are only on the order of mm/yr. The hard, complex structure of living beds provides habitats for numerous associated species not found on otherwise entirely sedimentary bottoms. Beds are degraded locally by dredging and other anthropogenic disturbances, and recovery is slow. They will likely suffer severe impacts worldwide from the increasing acidity of the ocean. Investigations of rhodolith beds with scuba have enabled precise stratified sampling that has shown the importance of individual rhodoliths as hot spots of diversity. Observations, collections, and experiments by divers have revolutionized taxonomic studies by allowing comprehensive, detailed collection and by showing the large effects of the environment on rhodolith morphology. Facilitated by in situ collection and calibrations, corallines are now contributing to paleoclimatic reconstructions over a broad range of temporal and spatial scales. Beds are particularly abundant in the mesophotic zone of the Brazilian shelf where technical diving has revealed new associations and species. This paper reviews selected past and present research on rhodoliths and rhodolith beds that has been greatly facilitated by the use of scuba

Are the reported coralline red seaweeds species for the Macaronesian region taxonomically still valid?

43rd European Marine Biology Symposium. Ponta Delgada, Açores, 8-12 de Setembro de 2008

A re-evaluation of Scinaia (Nemaliales, Rhodophyta) in the Azores.

Copyright © Springer-Verlag and AWI 2011.The genus Scinaia in the Azores is re-evaluated based on historical and recent collections. A combination of morphological and anatomical diagnostic characters was used for species segregation, and a key for Azorean species determination is presented. Anatomical information associated to the hair development is described for the first time for the genus. The occurrence of S. furcellata and S. interrupta is confirmed for the archipelago. The presence of S. acuta is reported for the first time in the Azores, representing a spread from Australia to the N-Atlantic and specifically into the Macaronesian region. Its occurrence in the archipelago and the Canaries is discussed as a possible introduction

New additions to the Azorean algal flora with ecological observations on rhodolith formations.

43rd European Marine Biology Symposium”. Ponta Delgada, Açores, 8-12 de Setembro de 2008

Life-cycle of Scinaia interrupta (Nemaliales, Rhodophyta)

Copyright © Springer Science+Business Media B.V. 2011.The life-cycle of Scinaia interrupta (A.P. de Candolle) M. J. Wynne was investigated in vitro using four irradiance regimes: 4, 8, 12 and 16 μmol photons mˉ² sˉ¹. A triphasic heteromorphic life-cycle was observed. Carpospores released by cystocarps of gametophytes collected in the field developed into filamentous tetrasporophytes, which produced tetrahedral tetrasporangia. Tetrasporangial development was accelerated under higher irradiance levels. Tetraspores germinated into filamentous protonemal gametophytes, initially identical to the tetrasporophyte. Filamentous gametophytes developed apical utricles and gave rise directly to the fleshy gametophyte. Further development of the fleshy gametophyte was not observed at the lowest irradiance regime (4 μmol photons mˉ² sˉ¹). The present study reports for the first time the influence of the irradiance regime on the initial tetrasporangial development and in the development of the fleshy gametophyte, and reinforces the importance of light intensity on Scinaia life-cycle. Production of apical utricles by the filamentous gametophyte is newly reported for the genus

The red algal genus Scinaia (Nemaliales; Rhodophyta) on the Azores Archipelago: a molecular approach with morphological and anatomical observations.

43rd European Marine Biology Symposium. Ponta Delgada, Açores, 8-12 de Setembro de 2008